<?php

class Persion {
    static $name = "lisi";
    const AGE = 22;


    public static function intro(){
        echo 'My name is '.self::$name.'<br/>';
        echo 'My age is '.self::AGE.'<br/>';
    }
    public static function intro1(){
        echo 'My name is '.static::$name.'<br/>';
        echo 'My age is '.static::AGE.'<br/>';
    }
}

class Stu extends Persion{
    static $name = "wangwu";
    public static function intro(){
        echo 'My name is '.self::$name.'<br/>';
        echo 'My age is '.self::AGE.'<br/>';
    }
}

Persion::intro();
Stu::intro();
Stu::intro1();